1. Field of the Invention
This invention relates to a door closer, and more particularly to a door closer with advanced manual locking to hold a door open.
2. Prior Art
A door closer is an apparatus to return an opened door to a closed position. Common door closers typically utilize a pneumatic or hydraulic cylinder with an end attachable to a door or door frame. The cylinder contains a piston with a rod extending from the free end of the cylinder. A compression coil spring is enclosed in the cylinder and pushes on the piston which transmits the force to the rod's extending end which is attachable to a door or door frame. The spring urges the piston to return to a maximum retracted position in the cylinder. With typical prior art devices, the speed at which the door closer returns the opened door to its closed position is adjusted by a bolt or screw attached to an end of the cylinder.
Usually a manually operated lock such as a cantable washer is mounted on the portion of the rod extending beyond the cylinder, to allow a user to arrest the door temporarily in an open position. Such a lock is cumbersome to the user and often results in the user pinching their fingers in between the washer and the cylinder. Its operation normally requires two hands, one being used to open and hold the door while the other is used to slide the washer on the rod until it contacts a stop provided on the cylinder. Upon release of the door, the stop cants the washer so that it grasps and arrests the rod and the door is held open. To unlock the door, the user must open the door further to relieve the force on the washer applied by the stop and then slide the washer along the rod to a location where it will not contact the stop for the entire retracting movement of the rod into the cylinder as the door closes.
Door closers with more conventional locks have been proposed in the prior art, but have not gained commercial acceptance. These devices incorporate automatic and semi-automatic locking techniques and are considerably more expensive and intricate than closers with manual locking as described and each have particular drawbacks peculiar to the mechanisms employed. These devices also fail to indicate to the user whether the mechanism is in a locking or unlocking mode, and if an uninformed user were to actuate the device, the door might close on the user unintentionally. Moreover, adjustment of existing door closers are cumbersome. These devices incorporate low profile adjustable screws which are obstructed from accesses by mounting brackets used to attach the cylinder to the door.
It can be seen then that a door closer is needed which is inexpensive, reliable, durable and more convenient to lock and unlock than existing door closers with conventional manually operated locks. The present invention address these problems, as well as others, associated with door closers.